1. Field of the Invention
The present invention relates to systems for controlling projection mode of image information recording media such as a roll of film and the searching mode of image being projected, and more particularly to a control device which is adapted to selectively switch an image-recorded film from its normal projection mode to other projection modes, such as a still projection mode, a slow motion projection mode, and a fading projection mode, or to switch it to searching and projection mode of each frame of an image.
2. Description of the Prior Art
A device has been disclosed in U.S. Pat. No. 3,290,987, in which code marks are provided on a roll of film, and said marks are detected to effect searching information recorded on the film.
A device has been disclosed in U.S. Pat. No. 3,520,596, which provides a film projector, wherein code marks for still projection are interposed in perforations of the projection film, and said marks are optically detected so as to switch the film projection mode from its ordinary projection mode to still projection mode.
The profile of such code marks is such that a plurality of marks of the optically same consistency is provided, or the difference of consistency is utilized to form a signal station of a given pattern profile and said pattern is varied each frame to serve as a searching number signal for said frame. The signals used in such prior arts, however, have such drawbacks that in case of a single code mark easily detectable, erroneous detection will often occur, and on the contrary, in case of a patterned signal, a method for recording signals becomes complicate.